Analog Switch Input¶

Overview¶

An Analog Switch Input reads a multi-position switch on a single analog
pin. Instead of one wire per position, the switch presents a different voltage
(or resistance) for each position, and this input decodes which position is
selected. Use it for rotary mode switches, multi-button steering controls and
resistor-ladder keypads.

Prerequisites & hardware¶

• A switch wired to one analog pin that produces a distinct level per position.
• Know each position's nominal value so you can set the recognition tolerance.
• External divider: the input does not provide an internal pull-up. In
  Resistors mode you fit an external pull-up resistor (and optionally a
  pull-down) to turn the switch's resistance into a voltage, and enter those
  resistor values so the controller can work out the switch resistance. In
  Voltage mode the switch presents the voltages directly and no divider is
  needed.

Add it in the app¶

1. Add a new input and choose Analog Switch Input as the type.
2. Select the pin the switch is wired to.
3. Give it a clear alias (e.g. Mode Switch).
4. Choose the mode and range. The two modes are mutually exclusive — pick
   whichever suits your hardware:
   • Resistors: enter the external pull-up (and pull-down) resistor
     values that form the divider.
   • Voltage: enter the voltage range (min/max voltage) the position sits
     in.
5. Set the precision and, for mechanical switches, the debounce timings.

Settings reference¶

Schema: config/AdcSwitchConfiguration.proto.

Common settings¶

Analog Switch Input also uses the shared settings — alias and pin.
See Common IO Settings.

Example — detect one switch position (Voltage mode)¶

Each Analog Switch Input recognises one position/level. This example detects a
single rotary position that sits at ~2.5 V:

1. Type Analog Switch Input, alias Mode Pos 2, on the switch's pin.
2. Mode Voltage, Range 5 V.
3. Min/Max voltage 2300/2700 mV — the window around that position.
4. Precision moderate so the detent maps cleanly to this position.
5. Enable filter, Delay 20, Hold 30 to settle between detents.

To decode every position of a multi-position rotary as its own signal, add one
Analog Switch Input per position — e.g. a 5-position rotary uses 5 inputs, each
watching its own voltage range. That is a valid setup but not the typical use;
most installs detect a single switch level.

Troubleshooting¶

• Wrong position selected / jumps between two: the levels are too close for the
  precision — tighten precision or space the positions further apart.
• No position recognised: in Voltage mode the reading is outside Min/Max
  voltage; in Resistors mode the entered pull-up/pull-down values don't match
  the resistors actually fitted.
• Position flickers when turning: enable the filter and raise Delay /
  Interspace.
• Voltage doesn't change with the switch (Resistors mode): check the external
  pull-up is fitted — without it the divider produces no voltage.

Related¶

• Analog Input — single analog voltage rather than a switch.
• Digital Input — single on/off contact.
• Mux Input — select between several inputs by a selector.